From the linked article:

"Almost no virus is protective against allergic disease or other immune diseases. In fact, infections with viruses mostly either contribute to the development of those diseases or worsen them.

The opposite is true of bacteria. There are good bacteria and there are bad bacteria. The good bacteria we call commensals. Our bodies actually have more bacterial cells than human cells. What we’ve learned over the years is that the association with family life and the environment probably has more to do with the microbiome. So one thing I would say is sanitizing every surface in your home to an extreme is probably not a good thing. Our research team showed in animals that sterile environments don’t allow the immune system to develop at all. We don’t want that."

Commensal bacteria are generally not airborne, whilst viruses that harm the immune system often are. So surface hygiene can be overdone, but air hygiene is a good idea.

Like your article states, there’s some evidence for exposure to benign microbes reducing allergies, but that is completely different than pathogens strengthening the immune system. Unfortunately some people seem to have remembered the hygiene hypothesis as meaning that microbes of all kinds are actually good.

There’s also a concept of immunity debt, although that’s more of an explanation for certain diseases being especially bad the year following COVID restrictions than an argument for exposure.

Hardly anyone even thinks about peanut allergies in a nation of 1.4 billion people (India) and kids don't drop dead like flies here.

But sure, let's just call the hygiene hypothesis tenuous.

I thought the recommendation was to introduce some peanuts at an early age in order to reduce the risk of getting peanut allergies?

Peanut allergy prevalence in India seems to be 0.3%, while in the western countries it's 1.5-3%.

Or even seasonal allergies to like pollen too, right? There’s just much more pressing breathing related issues to be concerned with (AQI etc)

That's not at all the same thing.

Could it be that people in India have different genetic makeup than people in other countries?

I mean, many populations have more/less risk of many physiological things. That's just how it goes.

Black men are at much higher risk of prostate cancer. White people of melanoma. As a man, I pretty much don't have to worry about autoimmune disorders because my risk is 1/10th that of a woman's. But, my risk of heart disease is much higher - even at the same weight!